On 30/07/2025 10.28, Kostiantyn Kostiuk wrote:
Reviewed-by: Kostiantyn Kostiuk <[email protected]
<mailto:[email protected]>>
@Thomas Huth Is this fix critical to merge during
code freeze?
I don't think so, the problem only occurs when compiling with
--enable-ubsan, so normal users should not be affected by this.
Thomas
On Wed, Jul 30, 2025 at 10:27 AM Thomas Huth <[email protected]
<mailto:[email protected]>> wrote:
From: Thomas Huth <[email protected] <mailto:[email protected]>>
When compiling QEMU with --enable-ubsan there is a undefined behavior
warning when running "make check":
.../qga/commands-linux.c:452:15: runtime error: applying non-zero
offset 5 to null pointer
#0 0x55ea7b89450c in build_guest_fsinfo_for_pci_dev ..../qga/commands-
linux.c:452:15
Fix it by avoiding the additional pointer variable here and use an
"offset" integer variable instead.
Signed-off-by: Thomas Huth <[email protected] <mailto:[email protected]>>
---
v2: Use an integer offset variable instead for checking for a NULL pointer
qga/commands-linux.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/qga/commands-linux.c b/qga/commands-linux.c
index 9e8a934b9a6..0c41eb97190 100644
--- a/qga/commands-linux.c
+++ b/qga/commands-linux.c
@@ -400,10 +400,10 @@ static bool build_guest_fsinfo_for_pci_dev(char
const *syspath,
Error **errp)
{
unsigned int pci[4], host, hosts[8], tgt[3];
- int i, nhosts = 0, pcilen;
+ int i, offset, nhosts = 0, pcilen;
GuestPCIAddress *pciaddr = disk->pci_controller;
bool has_ata = false, has_host = false, has_tgt = false;
- char *p, *q, *driver = NULL;
+ char *p, *driver = NULL;
bool ret = false;
p = strstr(syspath, "/devices/pci");
@@ -445,13 +445,13 @@ static bool build_guest_fsinfo_for_pci_dev(char
const *syspath,
p = strstr(syspath, "/ata");
if (p) {
- q = p + 4;
+ offset = 4;
has_ata = true;
} else {
p = strstr(syspath, "/host");
- q = p + 5;
+ offset = 5;
}
- if (p && sscanf(q, "%u", &host) == 1) {
+ if (p && sscanf(p + offset, "%u", &host) == 1) {
has_host = true;
nhosts = build_hosts(syspath, p, has_ata, hosts,
ARRAY_SIZE(hosts), errp);
--
2.50.1
